Spring Security权限框架理论与实战(五)- 自定义决策AbstractAccessDecisionManager

/**
 * Simple concrete implementation of
 * {@link org.springframework.security.access.AccessDecisionManager} that grants access if
 * any <code>AccessDecisionVoter</code> returns an affirmative response.
 */
public class AffirmativeBased extends AbstractAccessDecisionManager {

    public AffirmativeBased(List<AccessDecisionVoter<? extends Object>> decisionVoters) {
        super(decisionVoters);
    }

    // ~ Methods
    // ========================================================================================================

    /**
     * This concrete implementation simply polls all configured
     * {@link AccessDecisionVoter}s and grants access if any
     * <code>AccessDecisionVoter</code> voted affirmatively. Denies access only if there
     * was a deny vote AND no affirmative votes.
     * <p>
     * If every <code>AccessDecisionVoter</code> abstained from voting, the decision will
     * be based on the {@link #isAllowIfAllAbstainDecisions()} property (defaults to
     * false).
     * </p>
     *
     * @param authentication the caller invoking the method
     * @param object the secured object
     * @param configAttributes the configuration attributes associated with the method
     * being invoked
     *
     * @throws AccessDeniedException if access is denied
     */
    public void decide(Authentication authentication, Object object,
            Collection<ConfigAttribute> configAttributes) throws AccessDeniedException {
        int deny = 0;

        for (AccessDecisionVoter voter : getDecisionVoters()) {
            int result = voter.vote(authentication, object, configAttributes);

            if (logger.isDebugEnabled()) {
                logger.debug("Voter: " + voter + ", returned: " + result);
            }

            switch (result) {
            case AccessDecisionVoter.ACCESS_GRANTED:
                return;

            case AccessDecisionVoter.ACCESS_DENIED:
                deny++;

                break;

            default:
                break;
            }
        }

        if (deny > 0) {
            throw new AccessDeniedException(messages.getMessage(
                    "AbstractAccessDecisionManager.accessDenied", "Access is denied"));
        }

        // To get this far, every AccessDecisionVoter abstained
        checkAllowIfAllAbstainDecisions();
    }
}

/**
 * Simple concrete implementation of
 * {@link org.springframework.security.access.AccessDecisionManager} that uses a
 * consensus-based approach.
 * <p>
 * "Consensus" here means majority-rule (ignoring abstains) rather than unanimous
 * agreement (ignoring abstains). If you require unanimity, please see
 * {@link UnanimousBased}.
 */
public class ConsensusBased extends AbstractAccessDecisionManager {
    // ~ Instance fields
    // ================================================================================================

    private boolean allowIfEqualGrantedDeniedDecisions = true;

    public ConsensusBased(List<AccessDecisionVoter<? extends Object>> decisionVoters) {
        super(decisionVoters);
    }

    // ~ Methods
    // ========================================================================================================

    /**
     * This concrete implementation simply polls all configured
     * {@link AccessDecisionVoter}s and upon completion determines the consensus of
     * granted against denied responses.
     * <p>
     * If there were an equal number of grant and deny votes, the decision will be based
     * on the {@link #isAllowIfEqualGrantedDeniedDecisions()} property (defaults to true).
     * <p>
     * If every <code>AccessDecisionVoter</code> abstained from voting, the decision will
     * be based on the {@link #isAllowIfAllAbstainDecisions()} property (defaults to
     * false).
     *
     * @param authentication the caller invoking the method
     * @param object the secured object
     * @param configAttributes the configuration attributes associated with the method
     * being invoked
     *
     * @throws AccessDeniedException if access is denied
     */
    public void decide(Authentication authentication, Object object,
            Collection<ConfigAttribute> configAttributes) throws AccessDeniedException {
        int grant = 0;
        int deny = 0;
        int abstain = 0;

        for (AccessDecisionVoter voter : getDecisionVoters()) {
            int result = voter.vote(authentication, object, configAttributes);

            if (logger.isDebugEnabled()) {
                logger.debug("Voter: " + voter + ", returned: " + result);
            }

            switch (result) {
            case AccessDecisionVoter.ACCESS_GRANTED:
                grant++;

                break;

            case AccessDecisionVoter.ACCESS_DENIED:
                deny++;

                break;

            default:
                abstain++;

                break;
            }
        }

        if (grant > deny) {
            return;
        }

        if (deny > grant) {
            throw new AccessDeniedException(messages.getMessage(
                    "AbstractAccessDecisionManager.accessDenied", "Access is denied"));
        }

        if ((grant == deny) && (grant != 0)) {
            if (this.allowIfEqualGrantedDeniedDecisions) {
                return;
            }
            else {
                throw new AccessDeniedException(messages.getMessage(
                        "AbstractAccessDecisionManager.accessDenied", "Access is denied"));
            }
        }

        // To get this far, every AccessDecisionVoter abstained
        checkAllowIfAllAbstainDecisions();
    }

    public boolean isAllowIfEqualGrantedDeniedDecisions() {
        return allowIfEqualGrantedDeniedDecisions;
    }

    public void setAllowIfEqualGrantedDeniedDecisions(
            boolean allowIfEqualGrantedDeniedDecisions) {
        this.allowIfEqualGrantedDeniedDecisions = allowIfEqualGrantedDeniedDecisions;
    }
}

/**
 * Simple concrete implementation of
 * {@link org.springframework.security.access.AccessDecisionManager} that requires all
 * voters to abstain or grant access.
 */
public class UnanimousBased extends AbstractAccessDecisionManager {

    public UnanimousBased(List<AccessDecisionVoter<? extends Object>> decisionVoters) {
        super(decisionVoters);
    }

    // ~ Methods
    // ========================================================================================================

    /**
     * This concrete implementation polls all configured {@link AccessDecisionVoter}s for
     * each {@link ConfigAttribute} and grants access if <b>only</b> grant (or abstain)
     * votes were received.
     * <p>
     * Other voting implementations usually pass the entire list of
     * <tt>ConfigAttribute</tt>s to the <code>AccessDecisionVoter</code>. This
     * implementation differs in that each <code>AccessDecisionVoter</code> knows only
     * about a single <code>ConfigAttribute</code> at a time.
     * <p>
     * If every <code>AccessDecisionVoter</code> abstained from voting, the decision will
     * be based on the {@link #isAllowIfAllAbstainDecisions()} property (defaults to
     * false).
     *
     * @param authentication the caller invoking the method
     * @param object the secured object
     * @param attributes the configuration attributes associated with the method being
     * invoked
     *
     * @throws AccessDeniedException if access is denied
     */
    public void decide(Authentication authentication, Object object,
            Collection<ConfigAttribute> attributes) throws AccessDeniedException {

        int grant = 0;
        int abstain = 0;

        List<ConfigAttribute> singleAttributeList = new ArrayList<>(1);
        singleAttributeList.add(null);

        for (ConfigAttribute attribute : attributes) {
            singleAttributeList.set(0, attribute);

            for (AccessDecisionVoter voter : getDecisionVoters()) {
                int result = voter.vote(authentication, object, singleAttributeList);

                if (logger.isDebugEnabled()) {
                    logger.debug("Voter: " + voter + ", returned: " + result);
                }

                switch (result) {
                case AccessDecisionVoter.ACCESS_GRANTED:
                    grant++;

                    break;

                case AccessDecisionVoter.ACCESS_DENIED:
                    throw new AccessDeniedException(messages.getMessage(
                            "AbstractAccessDecisionManager.accessDenied",
                            "Access is denied"));

                default:
                    abstain++;

                    break;
                }
            }
        }

        // To get this far, there were no deny votes
        if (grant > 0) {
            return;
        }

        // To get this far, every AccessDecisionVoter abstained
        checkAllowIfAllAbstainDecisions();
    }
}